Update to v.1.0.3

- Added pause functionality
- Added a minor parallax effect
- The camera now pans vertically when high enough
- Collectible system has been split up in 2 parts:
       * Common Collectibles: these can be found all around
          the level
       * Rare Collectibles:  these are harder to reach and
          sometimes even hidden. Keep an eye out for them,
          because they are very valuable!
- The level has been expanded substantially, with some visual updates
- Various bug fixes